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Logopedics Phoniatrics Vocology
ISSN: 1401-5439 (Print) 1651-2022 (Online) Journal homepage: http://www.tandfonline.com/loi/ilog20
Childhood apraxia of speech: A survey of praxis
and typical speech characteristics
Ann Malmenholt, Anette Lohmander & Anita McAllister
To cite this article: Ann Malmenholt, Anette Lohmander & Anita McAllister (2016): Childhood
apraxia of speech: A survey of praxis and typical speech characteristics, Logopedics Phoniatrics
Vocology, DOI: 10.1080/14015439.2016.1185147
To link to this article: http://dx.doi.org/10.1080/14015439.2016.1185147
Published online: 31 May 2016.
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Date: 21 June 2016, At: 04:01
LOGOPEDICS PHONIATRICS VOCOLOGY, 2016
http://dx.doi.org/10.1080/14015439.2016.1185147
ORIGINAL ARTICLE
Childhood apraxia of speech: A survey of praxis and typical speech
characteristics
Ann Malmenholta,b
, Anette Lohmandera,b
and Anita McAllistera,b,c
Downloaded by [La Trobe University] at 04:01 21 June 2016
a
Division of Speech and Language Pathology, Department of Clinical Science, Intervention and Technology, Karolinska Institutet, Stockholm,
Sweden; bFunctional Area Speech & Language Pathology, Karolinska University Hospital, Stockholm, Sweden; cDivision of Speech and
Language Pathology, Department of Clinical and Experimental Medicine, Link€oping University, Sweden
ABSTRACT
ARTICLE HISTORY
Purpose: The purpose of this study was to investigate current knowledge of the diagnosis childhood
apraxia of speech (CAS) in Sweden and compare speech characteristics and symptoms to those of earlier survey findings in mainly English-speakers.
Method: In a web-based questionnaire 178 Swedish speech–language pathologists (SLPs) anonymously
answered questions about their perception of typical speech characteristics for CAS. They graded own
assessment skills and estimated clinical occurrence.
Results: The seven top speech characteristics reported as typical for children with CAS were: inconsistent speech production (85%), sequencing difficulties (71%), oro-motor deficits (63%), vowel errors
(62%), voicing errors (61%), consonant cluster deletions (54%), and prosodic disturbance (53%). Motorprogramming deficits described as lack of automatization of speech movements were perceived by
82%. All listed characteristics were consistent with the American Speech–Language–Hearing Association
(ASHA) consensus-based features, Strand’s 10-point checklist, and the diagnostic model proposed by
Ozanne. The mode for clinical occurrence was 5%. Number of suspected cases of CAS in the clinical
caseload was approximately one new patient/year and SLP.
Conclusions: The results support and add to findings from studies of CAS in English-speaking children
with similar speech characteristics regarded as typical. Possibly, these findings could contribute to crosslinguistic consensus on CAS characteristics.
Received 17 May 2015
Revised 10 March 2016
Accepted 21 April 2016
Published online 27 May 2016
Introduction
Childhood apraxia of speech (CAS) is a speech sound disorder (SSD) negatively affecting children’s intelligibility.
The disorder leads to a reduced ability to communicate,
which in turn affects participation. Children displaying
impaired intelligibility are assessed and diagnosed by
speech–language pathologists (SLPs). To date there is no
validated, replicable method for clinical diagnosis of CAS
(1), resulting in uncertainty whether studies on CAS examine the correct population, displaying core difficulties of
CAS or difficulties also seen in children with other SSDs.
The reported prevalence rates vary between 0.125% and
4.3% (2–5), which may reflect the difficulties to define the
diagnosis of CAS. The lowest estimates are based on clinical referral data (4), and the highest include children with
suspected CAS (5).
Several clinical studies have investigated key characteristics
for CAS reported by SLPs based on English-speaking children (Table 1).
Forrest asked SLPs attending a continuing education
workshop to name up to three characteristics that they felt
were necessary for a diagnosis of CAS. Altogether 50 different characteristics were listed. The analyses showed that the
six most frequent criteria accounted for 51.5% of all
KEYWORDS
Assessment; clinical
occurrence; consensus;
global speech
characteristics; inconsistent
speech production; selfrating; speech–language
pathologist; speech sound
disorders
responses; they were: inconsistent productions, general oromotor difficulties, groping, inability to imitate sounds,
increased errors with increased length, and poor sequencing
of sounds (6). In a follow-up survey gathered during conferences addressing the diagnosis and treatment of childhood
apraxia of speech, SLPs listed the most essential characteristics used to diagnose CAS (7). The result showed no
increased consensus among SLPs regarding key features of
CAS. A new question added, compared to the Forrest survey,
was if participating SLPs had read the American
Speech–Language–Hearing Association (ASHA) position
statement on CAS (8), and the outcome showed that 17%
had done so. The answers from these did not differ from
other SLPs concerning key features (7).
Aiming for consensus among researchers and practicing
SLPs, a literature review and a US national survey were conducted in order to define characteristics of CAS (9). This
query resulted in five top characteristics that were agreed
upon by at least 60% of researchers and SLPs showing ‘. . . a
greater amount of agreement regarding CAS diagnostic criteria than commonly believed’. The top five were: inconsistent
productions, difficulty with sound sequencing, groping or
struggle behavior, articulation errors, and poor or reduced
intelligibility.
CONTACT Ann Malmenholt
ann.malmenholt@ki.se
Department of Clinical Science, Intervention and Technology, Division of Speech and Language
Pathology, Karolinska Institutet, S–141 86 Stockholm, Sweden
ß 2016 Informa UK Limited, trading as Taylor & Francis Group
2
A. MALMENHOLT ET AL.
Table 1. Survey studies stating typical characteristics for CAS (in chronological order).
References
No of participants
Participants
Most prevalent characteristic
75
104
11
98
302
SLPs
SLPs
Researchers
SLPs
SLPs
Inconsistent productions, 14.1%
Difficulty planning speech, 78%
Inconsistent production, 90%
Inconsistent production, 55%
Inconsistency of errors, 50%
Forrest, 2003 (6)
Millspaugh & Weiss, 2006 (9)
Millspaugh & Weiss, 2006 (9)
Joffe & Pring, 2008 (10)
Meredith & Potter, 2011 (7)
Table 2. Overview according to Ozanne’s diagnostic model (13).
Cluster I
Vowel errors
Errors in phrases
Cluster II
DDK rate
DDK sequence
Errors in polysyllables
Oro-motor
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Errors not rules/processes
Poor phonotactics
Inconsistent articulation
Distortion
Cluster III
Groping
Consonant
deletion
Voluntary versus
Involuntary
Metathesis
Cluster IV
No babbling
Prosodic
disturbance
The ‘Ozanne model’ contains three levels: phonological planning (cluster I),
phonetic programming (clusters II–IV), and oro-motor control (clusters II–IV). To
be diagnosed with CAS, children should display deficits on all three levels.
Unsolicited information on CAS was received when asking SLPs about their clinical practice concerning children
with phonological problems. Altogether 61% of responding
SLPs reported uncertainty regarding differential diagnostic
criteria for children with suspected CAS. The responses
included inconsistent production, oro-motor problems, groping, sequencing problems, difficulty in copying sounds, distortions of vowels, and a history of feeding and drinking
problems as potential markers for CAS. Slow progress or a
resistance to therapy was mentioned to be behaviors not typically seen in children with phonological delay or disorder
thus indicating CAS (10). In a Dutch study the six most pronounced CAS speech characteristics reported by SLPs were:
difficulty sequencing articulatory movements, highly unintelligible speech, groping behavior, suprasegmental disturbances,
inconsistent speech errors, and articulation errors (11),
largely similar to the top six characteristic reported by
Forrest (6) despite different languages.
Mapping actual cases Guyette and Diedrich claimed that
characteristics of CAS are commonly seen in all children displaying any speech disorder of unknown origin (12). Ozanne
(13) studied 100 children with speech disorders of unknown
origin benchmarking previously mentioned motor planning
or programming problems (14–16). A cluster analysis of
the 18 behaviors thought to reflect an underlying motorprogramming or motor-planning disorder showed that
between 27% and 38% exhibited difficulties with diadochokinetic tasks, increased errors with increased load, and inconsistent productions, indicating that these characteristics are
not specific for CAS alone. The diagnostic model suggested
by Anne Ozanne (13) categorizes displayed speech errors to
their presumed underlying deficits constructing a speech output planning and programming model for the diagnosis of
CAS, as summarized in Table 2.
Speech motor control in typical developing children was
less mature in boys compared to girls up to the age of
5 years. The authors also observed a plateau in the
development of co-ordination skills between the ages of 7
and 12 years, with consistency increasing also after 12 years
of age, an important indication of the complexity of speech
motor development (17). The influence of increased utterance length and complexity on speech motor performance in
typically developing children (5-year-olds) and adults has
been found to result in increased errors in both children and
adults (18).
Different frameworks to describe key features and etiology
have been suggested (19). In response to the lack of consensus an Ad Hoc Committee on Childhood Apraxia of Speech
was formed to review the research background for CAS in a
technical report (20) and a supporting position statement
(8). The ASHA report led to a proposition of a definition of
CAS and consensus on three features observed in children
with suspected CAS in the literature: ‘a) Inconsistent errors
on consonants and vowels in repeated productions of syllables or words, b) lengthened and disrupted co-articulatory
transitions between sounds and syllables, and c) inappropriate prosody, especially in the realization of lexical or phrasal
stress.’ Another ASHA recommendation was henceforth to
use the term CAS–childhood apraxia of speech exclusively, a
term elsewhere referred to as speech delay–apraxia of speech
(SD-AOS), developmental verbal dyspraxia (DVS), developmental apraxia of speech (DAS), and developmental verbal
dyspraxia (DVD), to mention some.
Recently a checklist for CAS has been developed by
Edythe Strand and colleagues (21) and used as diagnostic
tool in some studies (1,21). To meet criteria, participants
should display evidence of four of the following 10 behaviors
in three or more Madison Speech Assessment Protocol
(MSAP) tasks: (1) difficulty achieving initial articulatory configurations or transitionary movement gestures; (2) syllable
segregation; (3) equal stress or lexical stress errors; (4) vowel
distortions and distorted substitutions; (5) groping; (6) intrusive schwa; (7) voicing errors; (8) slow rate; (9) slow diadochokinetic rates; and (10) increased difficulty with
multisyllabic words.
Murray and colleagues examined a sample of children
with suspected CAS and asked two experts to rate presence
and severity of CAS based on perceptual features of speech
samples plus the three ASHA consensus-based features and
Strand’s 10-point checklist (1). After using a discriminant
function analysis, they concluded that ‘Polysyllabic production accuracy and an oral motor examination that includes
diadochokinesis may be sufficient to reliably identify CAS
and rule out structural abnormality or dysarthria’ (1, p. 43).
For assessment of young or severely speech-impaired children with speech praxis difficulties, i.e. children not able to
produce polysyllabics, Strand et al. constructed the valid and
LOGOPEDICS PHONIATRICS VOCOLOGY
reliable test DEMSS—The Dynamic Evaluation of Motor
Speech Skill—further aiding the differential diagnosis of
CAS (22).
There is an ongoing effort to establish consensus on clinical diagnostic markers for CAS. Due to the historic lack of
consensus the body of research on the disorder has been
questioned since it may also include children with symptoms
currently not included in the diagnosis. Expanded information on current clinical knowledge of SLPs assessing and
treating children with CAS, speaking other languages than
English, would be of great value in order to enhance current
knowledge.
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Aim
The aim of this study was to investigate current knowledge
about the diagnosis of CAS and compare speech characteristics and symptoms in Swedish to those of earlier survey findings in mainly English-speakers. The following research
questions were posed: 1) How do Swedish SLPs rate their
clinical knowledge assessing and diagnosing children with
suspected CAS? 2) What speech characteristics and other
deficits do SLPs consider typical in Swedish-speaking children with suspected CAS? 3) How frequent is suspected CAS
in Swedish children seeing SLPs? What is the estimated
clinical occurrence?
3
appropriate from a list of 17 speech characteristics (Question
14). These listed characteristics, often stated as typical for
CAS in the literature, were chosen to avoid confusion due to
variations in terminology. The respondents were divided into
a less experienced (<10 years) and an experienced SLP group
(>10 years). Differences between the two groups on the 17
speech characteristics were tested with chi-square. A P < 0.05
was regarded as significant. A subgroup of SLPs who
reported having met with more than 100 cases of suspected
CAS was put together and labeled as ‘experts’.
The distribution of the answers on typical characteristics
was ranked and categorized according to the cluster analysis
presented by Ozanne (13). A total of 6 out of 17 characteristics (phonological deficits, language impairment, attention
deficits, learning difficulties, poor gross-motor and poor finemotor skills) were listed to capture described co-occurring
general features in the literature, e.g. academic difficulties (3)
or generalized motor incoordination (24).
Questions 16 and 17 asked for SLPs’ preconceived opinions and thoughts, in their own words, about observed cooccurring difficulties and important assessment considerations. The concluding summaries of these answers are more
qualitative and processed using content analysis.
The scale used in the question on how confident SLPs felt
assessing children with CAS (Question 20) had six scale
steps, ranging from very confident to very unsure. In the
analyses the answers were dichotomized to either confident
or unsure.
Method
A survey questionnaire was constructed, asking quantitative
and qualitative questions about the population of children
displaying the SSD of suspected CAS. The questionnaire was
tested in a web-based pilot study. Four clinically and academically experienced SLPs participated. Comments from the
pilot study concerned technical issues and choice of words,
and resulted in the final version that consisted of 22 questions (see Appendix).
Questions targeted the SLPs’ background (Questions 1 to
5), clinical accustomedness and theoretical knowledge regarding CAS (Questions 6–10 and 13–19), estimation of own
competence regarding CAS (Questions 20–22), and questions
regarding estimated occurrence of CAS in children at their
own clinic (Questions 11 and 12). Six questions are not
addressed in this paper, three questions due to their limited
interest for the international reader (Questions 1, 3, and 5)
and three (Questions 18, 19, and 21) because they survey
intervention and will be reported elsewhere.
We contacted SLP heads of departments throughout
Sweden asking for email addresses of SLPs working with preand primary school-aged children. The web-based questionnaire was distributed to 289 Swedish SLPs during
June–November 2011 using Google Docs Form to ensure
that answers remained anonymous. The participants volunteered by completing the survey targeting SLPs’ professional
know-how, not including any patient-specific data. Hence
this study was regarded to be outside the scope of the ethical
review board according to current guidelines. Respondents
were asked to select as many characteristics as they felt
Results
A total of 178 clinical SLPs from 19 of Sweden’s 21 counties
responded; this equals a survey response rate of 62%. The
response rate between different questions in the survey
varied with a mean response rate of 90% (Table 3).
SLP experience and knowledge on assessment and
diagnosis
Respondents were from different clinical settings and had a
range of clinical experience. Participating SLPs had graduated
from different universities between the years 1972 and 2011
Table 3. Response rate in percent specified for each
included survey question (see Appendix).
Question
Response rate (%)
2
4
6
7
8
9
10
11
12
13
14
15
16
17
20
22
96
97
94
98
97
98
96
89
82
96
96
96
38
74
97
97
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4
A. MALMENHOLT ET AL.
Figure 1. Different assessment approaches for CAS reported by Swedish SLPs.
(Question 2). Forty-one percent of respondents were in their
first five years of practice, 22% had from five to ten years of
experience, and 37% more than ten years of clinical experience primarily working with preschool and primary school
children (Question 9). Forty-four percent of the SLPs worked
in hospitals or public speech and language clinics, 12% at
university hospitals, 24% within child habilitation services,
9% in special pre- and primary schools for children with
speech and language disorders, 8% at private clinics, and 3%
in other work places (Question 4).
Figure 1 summarizes the main assessment approaches
which emerged when analyzing respondents’ answers on
what they considered important when assessing children
with suspected CAS (Question 17).
In Question 10, SLPs, diagnosing children with suspected
CAS, were asked to choose one or several codes from a
selected list of the International Classification of Diseases
(ICD-10) stating their typical use for patients with CAS. The
most frequently used diagnoses were oral and/or verbal
apraxia (R48.2) occurring in 44%, phonological disorder
(F80.0A) in 22%, a combination of phonological disorder
and oral motor developmental delay (F80.0A þ F80.0B) in
23%, and other ICD-10 codes in 11% of answers.
SLPs were also asked to report the sources of their theoretical and clinical knowledge regarding CAS. Possible alternatives were lectures during undergraduate studies (Question
6), lectures or courses after undergraduate studies (Question
7), or search for information about CAS by themselves
(Question 8). Courses included in undergraduate studies had
been undertaken by 68%, later courses or lectures by 54%,
and search for information on their own using different
sources (e.g. browsing the internet, reading studies obtained
via PubMed, asking colleagues specialized in speech motor
disorders) was reported by 83%. Three SLPs answered ‘no’ to
all three questions about knowledge base regarding CAS.
One diagnosed children with suspected CAS.
Twenty-nine percent of the SLPs perceived CAS to be a
disorder in its own right, 10% considered the disorder to be
part of or in co-morbidity with another disorder, 51% of the
SLPs experienced that some cases are clear cases of CAS and
some are part of or in co-morbidity with other disorders.
The alternative: ‘CAS is a consequence of another disorder’
was not agreed upon by any SLP, but 10% replied that they
did not know (Question 13).
When asked to share observations of co-occurring difficulties seen in children with suspected CAS (Question 16)
respondents raised different issues using the free text answering space. Most answers were clarifications and comments
on issues covered in general, often using a different terminology, compared to the listed typical characteristics
(Question 17) and statements about typical behaviors
(Question 15). The notion of variability in the ability to produce speech during different days was added. Some SLPs
observed additional co-ordination difficulties not only
obstructing smoothness of articulators and body movements
but also affecting the control of air flow, resulting in voice
initiation and voice quality issues.
When rating their own ability as SLPs to assess children
with suspected CAS 55% of respondents felt unsure and 45%
confident about diagnosing CAS (Question 20). A further
analysis of these figures was conducted based on the fact that
only half of the SLPs reported that they do assess and diagnose CAS (Question 10). The analyses revealed that out of
the SLPs not assigned to diagnose children with suspected
CAS, 29% felt confident about performing CAS assessment,
and 71% did not. Among the SLPs that assessed and
LOGOPEDICS PHONIATRICS VOCOLOGY
5
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Table 4. Typical characteristics of CAS in rank order from a SLP survey and a subgroup of experts (>100 CAS cases), fitted into the ASHA consensus-based features
(8), Strand’s 10-point checklist (21), and categorized according to the cluster analysis proposed by Ozanne (13).
Typical characteristics in CAS
Frequency of
selection of
characteristics
(n ¼ 171)
Frequency of selection of
characteristics by a subgroup of experts on CAS
(n ¼ 6)
Inconsistent production
Motor-programming deficits
Sequencing difficulties
Oro-motor deficits
Vowel errors
Voicing errors
Consonant cluster deletion
Prosodic disturbance
Phonological deficits
Resonance inconsistency
Poor fine-motor skills
Metathesis
Suprasegmental disturbance
Poor gross-motor skills
Language impairment
Learning difficulties
Attention deficits
85%
82%
71%
63%
62%
61%
54%
53%
44%
36%
34%
23%
19%
12%
10%
5%
4%
67%
100%
67%
83%
50%
67%
67%
50%
2%
33%
0%
2%
0%
0%
0%
0%
0%
ASHA
consensus-based
features (2007)
Strand’s 10-point
checklist (2011)
a
c
b
b
c
b
b
c
1
8
1
4
7
4
3
Clusters according to
Ozanne’s model
(presented in 1995)
I
III
II
II
I
II
III
IV
II
c
2
III
IV
Key: a ¼ Inconsistent errors on consonants and vowels in repeated productions of syllables or words; b ¼ lengthened and disrupted co-articulatory transitions
between sounds and syllables; c ¼ inappropriate prosody, especially in the realization of lexical or phrasal stress; 1 ¼ difficulty achieving initial articulatory configurations or transitionary movement gestures; 2 ¼ syllable segregation; 3 ¼ equal stress or lexical stress errors; 4 ¼ vowel distortions and distorted substitutions;
5 ¼ groping; 6 ¼ intrusive schwa; 7 ¼ voicing errors; 8 ¼ slow rate; 9 ¼ slow diadochokinetic rate; 10 ¼ increased difficulty with multisyllabic words; I–IV, see
Table 2.
Figure 2. The 17 speech characteristics typical for CAS clustered using Ozanne’s model and co-occurring characteristics.
diagnosed CAS 59% reported that they felt confident and
41% that they felt unsure. Eighty-nine percent of all responding SLPs declared a lack of competence regarding CAS
(Question 22). The question regarding additional training,
‘What kind of supplementary training would meet your
needs?’, was answered in free text, describing different areas
of interest. One-quarter (25%) stated a need for an update
on current literature and research, another quarter (23%)
knowledge about intervention. Knowledge about evidencebased practice was called for by 5% and about diagnosis/differential diagnosis by 15%. Five percent of responding SLPs
reported an interest for CAS in a broader context or regarding co-morbidity. Settings for education and training were
suggested: coaching by experienced colleagues (11%) and
through workshops or case discussions or video examples by
14% of the responding SLPs. Three SLPs were interested in
consensus discussions with Swedish examples.
Speech characteristics and other deficits seen in CAS
The 171 respondents selected between 2 and 17 characteristics from the list of 17 characteristics (Question 14). A total
of 1043 characteristics were selected by the respondents; the
mode value was 7.2. The characteristics were fitted into the
consensus-based features from ASHA’s technical report (20),
Strand’s 10-point checklist (21), and clustered according to
Ozanne’s model (13) showing overlap on eight characteristics, as seen in Table 4.
Dividing respondents into less experienced (n ¼ 109) and
more experienced (n ¼ 64) SLPs, based on years of practice,
showed that the less experienced SLPs significantly more
often registered vowel errors as a typical speech characteristic
for CAS. Answers for other typical characteristics were not
significantly different between groups. The expert group
(n ¼ 6), consisting of SLPs seeing more than 100 cases of
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6
A. MALMENHOLT ET AL.
suspected CAS, showed a slightly different pattern, even more
in line with characteristics from the ASHA consensus-based
features, Strand’s 10-point checklist, and Ozanne’s model.
Clustering all survey answers on typical speech characteristics revealed that 81% of SLPs listed characteristics from all
three clusters (I–III), sufficient for the three levels in the diagnostic model (Figure 2); a similar distribution was found for
clusters I, II, and III, whereas characteristics in cluster IV
were chosen somewhat less frequently. The remaining six
characteristics not included in any of the used models were
grouped in four areas of difficulties, showing that almost half
of the answering SLPs perceived that CAS patients display
language impairment as well. Motor difficulties, i.e. poor fineand gross-motor skills, were noted to be a typical characteristic by one-third of the SLPs. Learning difficulties and attention deficits were not reported to be typically co-occurring.
Statements about typical behaviors seen in children with
CAS had to be agreed with by the respondents (Question
15). In total 92% shared the opinion that ‘children with CAS
make very slow progress (in therapy)’, and 58% felt that
‘patients (with CAS) were resistant to therapy’. ‘Regressing
after a treatment break’ was an experience shared by 58%,
and ‘persistent speech difficulties at school age’ was noted by
84% of the SLPs. ‘Difficulties with reading development’ was
observed by 24% and ‘difficulties with writing development’
by 23% of the SLPs.
Estimation of clinical occurrence of CAS
The mode value for rated clinical occurrence, consisting of
an estimation of the number of patients showing difficulties
with verbal praxis in percent, was 5% over all clinical settings
in this study (Question 12). Answers ranged from 0% to
70%. The mode value for clinical occurrence estimated by
SLPs working at habilitation centers was twice as high
(11%), including one estimation of 70%. About half of the
SLPs (52%) reported seeing between 0 and 1 new patient
with suspected CAS per year in their clinic, and answers
ranged from 0–20 patients/year (Question 11), including
those specialized in motor speech disorders.
Discussion
In this study comprehensive information about clinical SLPs’
knowledge concerning children with suspected CAS was collected. The overall aim was to investigate current knowledge
about the diagnosis of childhood apraxia of speech (CAS) by
letting Swedish SLPs share their clinical experience and
observations of typical speech characteristics and other
symptoms in these children. They were also asked to estimate clinical occurrence, e.g. the number of patients in their
clinical population. In addition, we wanted to compare
speech characteristics and symptoms to those of earlier survey findings in mainly English-speakers.
The survey response rate and distribution of SLPs
throughout the country and in different work settings make
it likely that the responding SLPs, despite the lack of
responses from two counties, together represent the current
praxis, knowledge, and clinical competence in Sweden.
SLPs’ experience and knowledge on assessment and
diagnosis
Assessment approaches differed, reflecting the absence of
consensus on a specific assessment approach for CAS in
Sweden. At present SLPs administer their own test batteries
reflecting their view of CAS as a disorder of primarily phonologic/linguistic and/or motor difficulty. A disparity was
also seen in the reported ICD-10 diagnoses. Differences in
SLP education in the field of motor speech disorders and, in
particular, regarding CAS during the past decades could also
explain this disparity. A theory-based test battery for children
in Swedish, as in other countries and languages, with the
purpose to differentiate between speech sound disorders is
needed.
In this survey no question mentions severity of CAS manifestations or age of the children affected. In children with
milder symptoms, where suspected CAS is to be differentiated from phonological delay and/or oro-motor difficulties,
some children might have been diagnosed with a combination of diagnoses, in this survey used by 23% of SLPs. The
use of other diagnoses might reflect an insecurity concerning
the diagnosis of CAS and neurological disorders in children.
Answers from experts (n ¼ 6) indicate that SLPs with experience of more than 100 cases of suspected CAS have
enhanced diagnostic skills regarding differentiating phonological and speech disorders from oral motor and speech
motor disorders. The age of the child is another factor influencing and changing the manifestations of CAS in different
children and over time in the same child (25).
Actively searching for information and knowledge on their
own was reported by 83% of SLPs. Due to the uncertainty of
the disorder and new developments in the field this must be
seen as a highly adequate method to update theoretical knowledge and clinical competence. About one-third of SLPs in
this survey viewed CAS as a defined, exclusive disorder, but
10% had not experienced clear-cut cases of CAS. About half
of the SLPs reported that they had experienced clear-cut
cases of CAS but also children displaying CAS symptoms as a
part of or in co-morbidity with other disorders. This diversity
of clinical experience and viewpoints on CAS reflects the
multi-faceted character of the disorder and the influence of
different work settings and clinical populations.
Speech characteristics and other deficits seen in CAS
The ranking of typical speech characteristics in CAS corresponded largely with other surveys of English-speaking SLPs
(6,7,9,10). Forrest (6) concluded that her study on diagnostic
criteria was limited due to predetermined instructions (i.e.
provide up to three criteria for diagnosing CAS). In the present study the limitation was in the list of predetermined,
typical characteristics for CAS (i.e. the SLPs could not use
their own words, and the terms provided were not additionally defined), yet the mode for the number of chosen characteristics was over seven, close to the number repeatedly
stated in other surveys. More than 50% of the SLPs in the
present study listed as many as seven characteristics, with
inconsistent production being the most common (85%), also
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LOGOPEDICS PHONIATRICS VOCOLOGY
mentioned as the most prevalent characteristic in several
other studies (6,7,9,10). Motor-programming deficits (82%)
described as lack of automatization of speech motor movements (i.e. a global term including groping and voluntary
versus involuntary speech movements) (14,16) is a feature
difficult to capture in one term but is probably also reflected
in sequencing difficulties (71%) (11,14). Oro-motor deficits
were marked by 63% of the SLPs, also supported by several
studies (14–16). Vowel errors (62%) (14,16), voicing errors
(61%) (26), consonant cluster deletion (54%) (14,26), and
prosodic disturbance (53%) (14,16) are all difficulties alerting
SLPs. When comparing our findings with the three consensus features from the ASHA position statement (8), Strand’s
checklist (21), and the ‘Ozanne model’ (13) they correspond
to a great extent for all surveyed SLPs. Furthermore, the
characteristics identified by the expert group were even more
in line with current models and checklists, apart from the
features of prosodic and suprasegmental disturbance. A possible explanation for this could be that experts see more children with severe difficulties, hence less speech output, which
is required for assessment of prosodic difficulties. Our findings in Swedish-speaking children are in line with findings
across studies from English-speaking countries (6,7,9,10) and
a report from Dutch (11) and Danish children (27), suggesting shared characteristics of children with CAS across these
Germanic languages. It would be interesting to study how
stable these characteristics are across languages.
We found one significant difference between experienced
and less experienced SLPs: the less experienced SLPs registered vowel errors as a typical speech characteristic for CAS
more often. Since experience is related to years post exam in
the present study, it is reasonable to interpret this as more
updated knowledge on key speech characteristics.
One-quarter of responding SLPs perceived patients with
CAS as having difficulties in reading and writing development, but just 5% estimated that CAS patients had learning
difficulties. Other deficits in language, reading, and writing
skills at school age are reported in children with CAS, despite the articulation difficulties being partially resolved (28).
Probably a broader view on CAS with a multiple domain
framework can explain the numerous and varying core features of CAS displayed as auditory-perception encoding and
memory and transcoding deficits (23). Future research in
CAS would benefit from more detailed descriptions of the
subjects’ core and co-occurring difficulties.
Furthermore, many SLPs (81%) displayed knowledge of
current theoretical frameworks and awareness of typical
speech characteristics in CAS. This is a positive finding, considering the impact a correct diagnosis may have on individualized intervention plans and accuracy of prognosis.
In the body of CAS literature much effort is spent on
finding diagnostic markers in order to specify the diagnosis
of CAS and distinguishing it from other subsets of speech
sound disorders (4,23,29). There is a need for evidence-based
assessment of children with CAS and for consensus on overt
speech characteristics and their presumed underlying deficits.
However, a cluster of diagnostic markers might be clinically
appropriate in order to differentiate these children from children with other speech sound disorders (1,13,22,23).
7
Survey reports on SLPs’ knowledge about CAS characteristics show similar presentations across studies. This could
reflect a growing knowledge on speech characteristics in
CAS. If international consensus on the characteristics of children with CAS is emerging, and CAS characteristics are
shared between languages, this would have major implications on future, shared diagnostic methods, facilitating
research collaborations and studies including larger, international samples.
Estimation of clinical occurrence of CAS
The estimated clinical occurrence with a mode value of 5%
reflects different work settings, given that the highest, outlying, estimate (70%) came from a clinician working at child
habilitation services. Other high estimates (25%–50%) were
made by seven colleagues from different work settings, in different parts of the country, and with varying years of experience. Two of these SLPs still rated their ability to diagnose
CAS as unsure. The other six felt more certain about their
own ability to diagnose CAS. One SLP reported seeing ‘some
signs of dyspraxic involvement in about 50%’. This reflects
that some SLPs have specialized in motor speech disorders,
hence mostly seeing patients with CAS or dysarthria, leading
to these high numbers in their caseloads. Asking informally
for information on clinical occurrence is not comparable to
calculations of prevalence and incidence but may give an indication of the occurrence of CAS in pre- and primary school
children seen in Swedish SLP clinics. The quest in this study
was to describe SLPs’ clinical reality, and the diversity of
answers highlights the need for formal calculations. Even the
variance of reported prevalences in the literature, from
0.125% to 4.3% (2–5) raises questions about descriptions and
inclusion criteria in research studies, possibly also reflecting
lack of agreement on diagnostic criteria over time. The somewhat higher occurrence of CAS reported by Swedish SLPs
could mirror the large number of vowels in Swedish, distinguished by subtle articulatory and durational properties (30).
This may also indicate a need for more in-depth training
regarding judgement of vowel quality and prosodic features.
The overall low occurrence reminds us that CAS occupies
a small portion of SLP caseloads. This in turn may lead to a
lack of knowledge, experience, and confidence within the
profession and a need for continued education considering
research results in the field. This could be resolved by specialization of SLPs with a recognized competence in motor
speech disorders, a suggestion already made in ASHA’s position statement (8).
Methodological concerns
The 17 typical speech characteristics listed were presented
without definitions. This makes it precarious to control the
respondents’ understanding of the listed characteristics in
detail. However, we presuppose that all SLPs have specific
knowledge about speech characteristics, and judging by the
answers most SLPs seemed to have knowledge about the
included speech characteristics. Our aim was to explore
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8
A. MALMENHOLT ET AL.
present knowledge of a sample of SLPs. The respondents had
graduated during a time span of 39 years, yet significant discrepancies were found only regarding one CAS speech characteristic, namely vowel errors.
During the construction of this survey no weighting of
speech characteristics was performed. However, in the analysis the 17 characteristics were distributed into Ozanne’s
model consisting of four clusters which resulted in similar
frequencies (90%–96%) for clusters I, II, and III. Cluster IV
showed a somewhat lower frequency (72%), probably
because cluster IV consists of only two characteristics, one
being deviant prosody and the other an anamnestic feature
regarding no history of babbling, not included in the present
survey. Prosodic errors, reflected in vowels and sonorants,
are difficult to assess especially in children with multiple
speech disorders and limited speech production, which often
is the case in children with more severe CAS (31).
The survey question with the lowest response rate
(Question 16) was about observations made on co-occurring
difficulties in children with CAS. However, few new topics
were raised when the SLPs were given the opportunity to
answer in their own words. This might reflect the broadness
of the survey, or it could be due to the fact that respondents
were focused on deficits concerning speech characteristics
and not more general characteristics. SLPs may not routinely
ask for co-occurring difficulties.
A drawback to distributing the survey anonymously was
that it ruled out the possibility of sending out a reminder.
On the other hand, we presume that answers are sincere.
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The results support and add to findings from studies of CAS
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Ann Malmenholt
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Anette Lohmander
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Anita McAllister
http://orcid.org/0000-0003-2208-0630
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Appendix
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Survey questions
Questions in bold are addressed in the present article.
1
2
Where did you study to become a speech–language pathologist?
Which year did you graduate?
3
Which county are you working in?
4
5
What type of setting are you working in?
Hospital; university hospital; public speech and language clinic; private clinic; child habilitation services; special pre- and primary school for children with
speech and language disorders; other working places
How many SLP colleagues seeing pre- and primary school patients do you have at your setting?
6
Was there a lecture about CAS during your undergraduate studies?
7
Have you participated in lectures or courses after your undergraduate studies?
8
Have you searched for information about CAS on your own?
9
For how long have you been working with pre- or primary school-aged children?
<5 years; 5–10 years; 11–15 years; 16–20 years; >20 years
10
Do you assess and diagnose children with CAS? yes/no
If you do, what ICD code do you use? (Choose one or multiple answers)
F80.0A; F80.0A þ F80.0B; R48.2; R48.2A; R48.2B; other
11
Approximately how many children displaying CAS have you met?
(Space for free answer)
12
Approximately what percentage of patients on your caseload do you consider to have difficulties with verbal praxis?
(Space for free answer)
13
I consider CAS to be: (Choose one or multiple answers)
a diagnosis in its own right, not necessarily coexisting with other disorders
part of or in co-morbidity with other disorders such as SLI, ADHD, ADD, dyslexia, cerebral palsy, Down syndrome, Rett syndrome, or other disorders
a consequence of other disorders
I do not know
14
Typical symptoms for children displaying CAS are: (Choose one or multiple answers)
Inconsistent production; motor-programming deficits; sequencing difficulties; oro-motor deficits; vowel errors; voicing errors; consonant cluster deletion;
prosodic disturbance; phonological deficits; resonance inconsistency; poor fine-motor skills; metathesis; suprasegmental disturbance; poor gross-motor skills;
language impairment; learning difficulties; attention deficits
15
Children with CAS: (Choose one or multiple answers)
Make very slow progress; make expected progress; are during periods almost resistant to therapy; regress after treatment break; have persistent speech difficulties at school age; have difficulties with reading development; have difficulties with writing development
16
Co-occurring difficulties you have observed in children with CAS?
(Space for free answer)
17
If a child is suspected of having CAS, what do you consider to be important during assessment?
(Space for free answer)
18
What do you consider to be most important when treating children with CAS?
19
If you have any experience treating children with CAS, please share examples of successful intervention.
20
How secure do you feel assessing children with CAS?
Very confident; confident; fairly confident; fairly unsure; unsure; very unsure
21
How secure do you feel when treating children with CAS?
22
Do you consider yourself lacking competence concerning CAS?
yes/no
If yes: What kind of supplementary training would meet your needs?
Questions 1, 3, 5, 18, 19, and 21 are not addressed in the present article.
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